This invention relates to speech processing apparatus and methods.
In complex equipment having multiple functions it can be useful to be able to control the equipment by spoken commands. This is also useful where the user's hands are occupied with other tasks or where the user is disabled and is unable to use his hands to operate conventional mechanical switches and controls.
The problem with equipment controlled by speech is that speech recognition can be unreliable, especially where the voice of the speaker is altered by environmental factors, such as vibration. This can lead to failure to operate or, worse still, to incorrect operation.
Speech signal processing can also be used in communication systems, to improve the quality of speech and reduce noise. Where, however, the speech is severely degraded, such as by vibration or by a high `g` loading, the processing equipment may not recognise the input as being a speech signal and may therefore remove vital components of the speech signal by filtering. The processing equipment can, therefore, in some circumstances lead to a reduction in the speech information.